Expansion rail joint



Aug. 15, 1950 H. o. HOFFMANN EXPANSION RAIL JOINT 2 Sheets-Sheet 1 Filed 001;. 27, 1943 EFF Aug. 15, 1950 H. o. .HOFFMANN EXPANSION RAIL JOINT 2 Sheets-Sheet 2 Filed Oct. 2'7, 1943 Patented Aug. 15, 195

UNITED STATES, OFFICE XPANsiON RA 'L'J M'. I Hans Otto Hoffmann, Lausanne, Switzerland Attica-roll atar 2%, lialslriarn 597,813

' L v In Switzerland June 28, 1943 It is known that'a railway wheel rolling over the gaps at joint between the ends of rails causes concussions, whereby the permanent way; and

also the rolling material are'subje'c'ted to strong wear. Due to the fact that,'late1y, thespeed of trains has been considerably increased, also the weight of the rolling material, including the net load, these inconveniences have attained addef3 Claims.- (01. 238-219) 3'fari'd 3'. Toward their ends the profiles of the rails," 3 and 3' are altered from the standard profile of 'a fiat base or foot and a bulging head, with'an i'ntermediate, comparatively thin, sup- 5 'portingweb, to a profile in which the portion between the base and the head is as thick as the'head and may become thicker downwardly so l by the term full-profile. Such a development permits expansion of the rails. This task is accomplished by the present invention.

The present invention refers to an expansion rail joint, whereby the ends of the rails to be connected, which are attached, at a certain distance from each other, to rail chairs, have full profiles, i. e. the railehead is not undercut, and

are provided with a groove each, in the centre, in the longitudinal direction of the'rails, an interchangeable connecting-web being positioned on shoulders formed by the grooves'in the ends of the rails, its length being dimensioned in such a manner that, on both sides of its ends, in the grooves positioned in the rail-ends, expansion gaps are provided, this connecting web being immovably held fast, independently of the rails, by

down, at least, to a position between thebearing-plates of the rail chairs. I l

The enclosed'sketch shows two embodiments of the object of the prcsent'invention'by way of example. The sketch shows:

bodiment of an expansion rail joint, partly in section;

Fig. 5 is a top-view thereof; Fig. 6 a section on theline IIII in Fig; 5.

v On the tie l of double width,according to the first example, the ends of the rails 3 and 3'reiispectively are wedged in such'a manner in two rail chairs 2 andZ' respectively that'there is a r v space D betweenthe frontsurfa'ces ofthe rails 55 respectively in the longitudinal direction of the of the enjds of the rails'3 and 3 can be effected by, welding full-profiled end-pieces to the ends of rails of standard profile. These end-pieces of the rails 3 and 3 can, however, also be manu- 'factured of cast steel in one piece. In the rail chairs 2 and 2? respectively, the rails 3 and 3 respectively are held on the exterior part by means 'of a steel key 4, provided with a spur 5, which is guided between the rail chairs 2 and 2' in such a manner that it can move in a vertical, but

not in a horizontal direction. A head 6 at the upper ends of the rail chairs 2' and 2 prevents the steel key 4 from getting out of the upper j'partpf the space between the rails 3 and 3',

andthe rail chairs 2 and 2 by means of wooden foxwe'dges, the inner part 1 of thesewedges being' secured against dislocation in the longitufdinal direction by a channel 8 screwed. on to them, reaching down between the bearing-plates of both rail chairs 2 and 2' and, thereby acting as an anchor; The exterior part of the wooden fox wedges,'however, can be moved in order to tighten up the wedge. in a longitudinal direction. The inner part 1 is narrower at its upper than at its 'lower p art ,,whereas the outer part 9, inversely,

J aspur provided on its lower side and reaching is wider at its upper than atjits lower part, in such a manner that the inner part i is held by the outer part 9, which also is secured by means 'of a head at the upper part of the rail chairs 2 40 and 2. Incase of loosening of the wooden fox Wedges 1, 9, the steel key idrops down, under the effect of its weight and, thereby, secures the keying, sliding down the slightly inclined side 1 surface of the ends of the full-profiled rails 3 v and 31and, for this reason, any dangerous loosen- 'ing cannot'take place. The arrangement of the steel key 4, which strictly takes up the forces Qproduced, on the outer part of the rails 3 and '3', provides for the fact that the rails are always .50 under strain from the inner to the outer part,

due to the lateral components of the forces produced by the rolling material.

The full-profiled ends of the rails 3 and 3' are provided, in the centre, with grooves It and I0 3 rails. These grooves Iii and do not extend from top to bottom of their entire length in one piece, but form shoulders ll and II respectively. A connecting-web I2 is inserted into the grooves and I6, and this web lies on the shoulders H and II. On its lower part, this connecting-web is provided with a spur l3, which reaches down to below the base of the rail, at least to the upper edge of the tie, its end being fitted into the bearing-plates of both rail chairs 2 and 2', in such a manner that the connecting-web I2 cannot be dislocated. The length of the grooves Ill and Ill, on the one hand, and of the connect-in'g web 12; on the other hand, is dimensigned in snch a way that there is an expansion gap (1 and d respectively on each side of the 'connecti 'web 12, whereby the sum of the lengths of these expansion gaps d+d, is always equal to the distance P, we in which the front surfaces of the rails 3 and 3 lie apart irom each other. The convexity o f the heads of rails "3 and 3' is gentlych'ani fere'd up be he plane of "the upper edges of the grooves -lll'fand In respectively, with which the surface of contact or the common-swab i2 lies flush. "0' eng'th exceeding the'm'axin'iumwidth or the ex ansiongaps d and'd respectively, the upper edges of "the grooves l0 and ID lie in the plane .oftne surface of contact of 'th'e connecting-web l2. and from there the "side 'walls or the 'e'nds'of the rails 3' and '3" are charhfered'and rounded on towards the'ends o f'the'rails. The purpose of this arrangement is to gradually force even a wheel hot rolling normally on the entire width of the rail-head to roll of: ion jth'e connecting-web "r2,

thereby avoiding oncussions, under all circumstances, when running ever rail joints.

in the case or the exp nsion ran jointdes'cribed "above, both rails '3and 3 can expand independ- Yefn tiy from each other. "In Fig, Lwnereny an illusfti ation of this .relation is furnished, the ,rail 3 is with maxi'riiumexp'ansion, whereas the {rail 3' does not expand at all. 'A particular advantage is ofiered by the symmetric formation of the ends of the rails andof the'coniiectifig-w'eb 12;, both as regards the longitudinal and the transverse axis, whereby the laying of the lines is considerably simplified. The expansion ran joint desc'ribed works in such a manner that 'th'e'ior- 'r'nation of cracksand steps at the ends of the rails is avoided. If one of the ran-ends Sinks ender the wheel load, the. con ecting-web ,1'2

fame-sings, and as soon as it isfaffected by the j'lbad, it act on'the rail-end lying opposite, by

loading it. 'The 'expansionjoint, therefore,' 'works in an elastic manner, thus ensuring therunning- "through oi r'oi mg loads, without Qa'iising confcuss'ions. The depression of the rails under'the loaiand also the previouslifting error the rails areeflected in a supple manner.

The development or the expansion ran joint,

according to the present invention, perrnits 'the use of ny length of xpansion gaps. By keying, orothefwise anchoringthe rails on ties, the normally unimpeded expansion of rails "can, under certain circumstances, be checked "to avery con [,s'iderable extent, according to requirements, by

leasing on modern knowledge of longrail track laying. Inasmuch as the connecting-web 12 is arranged to be immovable, independently of the rails 3and 3., item; be ascertainedatany timefig K v 'si'on rairj'oint' may generally be considered as satisfactoryin order to reduce the length of the by comparing the expansion gaps d and d'at both ends of the connecting-web l2, Whether the checking of the expansion is b eing'ob'served, 'and 'accntrm regarding the attitude of the rails in other respects is rendered possible. This is par- 4 ticularly important, because it is known that rails have the tendency to creep and to push together to groups, and this should always be avoided in the case of long-rail lines. According to the present invention, it can be ascertained in an indisputable manner, and at an opportune moment, which of two or several rails starts creeping, and. whether the checking of expansion to be provided is adhered to, whereby it is possible to meet any inconvenience arising in due time. The checking of the expansion is efiected by means of the resistance of ballast, and possibly also by additional arrangements at the joint itself, whereby ribbed-ironwedges are advantageously employed,

:With full profiles at their ends.

instead of wooden wedges.

which are worn out, can easily ber'eplaced and freshened up. All wedges areaounded off and, thereby the wear and tear is negligible. Worn out pieces of rail-ends can be repaired agam by a welding operation. 7 Inth'ee'xalnple of an expansion rail joint shown in'Fi'gs.4'-6, 14 rep esents the tie or double Width, "l"5 'a'n'd l5 the rail chairs, and I5 and IS the rails. [Also these .rail's l6 and I6 are provided 7 On the outer part, the rails 1'6 and T6 are held in the rail chairs I5 and 15' by means of a steel-key l1, whichis lminoVablyJheld by 'a projecting part fl'B, lio opei'ati'ng "between the rail chairs l5 and 15'', "in the longitudinal direction of the rails.

10h the inner part of the Trails 'IB'and le wooden f ick-wedges are arranged, their under part [9 being" secured'iagains't dislocation in a longitudinal dii'ection'by me'ans of an anchor 20 reaching "into the "bearing-plates of "the rail chairs I5 and [5, The outer part 2'l'o'f the wooden fox wedges "is, 'liowe'i er, movable in a longitudinal direction, inorderto tighten 'up'the wedges. So far, the remand-n is "exactly the same, as in the example described above. The full-profiled ends of the rails l6 ant-1T6" are provided, in the centre, with 'gio'oves 22 and 22' "respectively running in a longitudinal direction, which also do not extend fl'flm toptobottom'o'f their entire length in one piece; but "formsho'ulders 1231and 23 respectively.

A connecting-web '2'4'is inserted into the grooves "22 ans-'22:, this 'we'b being positioned on the shoulders23fand'f23and provided, on its lower pa "with aspur 2'5, whichreaches down, at least,

jto thefupperedgeofjthe tie, and is held between tliejbEaring plateS 'ofth'e rail chairs l51and f5.

f'lfheflefii'gth or the grooves 22 and 22, on the one hand, and "of the connecting-web 24, on the 'dther hand, isdirnensioned in'such a manner that ,'foh*eachside'ofthe connecting web an exon *g'ap dl and "di' remains open. The middle "part '26 of the connecting web 24 has a railhead profile with chamfered and rounded foifj'edfges 'on'both sides, In order to take up this rail-headprofile'd middlepart 26 of the'connectfexpansion gaps on the side surface of the rail ftothel'ength oi the expansiongaps di and d1; it however, of particular advantage, provided an expansion rail joint should exceptionally lie in a rail-curve, in order to safely avoid climbing of the wheel flanges, even in the case of strongest contraction of rails, i. e. maximum opening of the expansion gaps.

I claim:

1. A rail joint especially intended for joining ends of rails of great lengths spaced apart at their ends by substantial gaps so as to provide for expansion thereof Without application of stress in the rails which rails throughout the part of their lengths remote from their ends are comprised by rail base flanges, wheel supporting heads and webs of less width than the heads supporting said heads, the webs of said rails in the vicinity of the adjacent ends being thickened laterally so as to be thicker than the webs remote from the end portions and of substantially the same thickness as the width of the rail heads, the upper portions of said rail ends each being provided with longitudinally extending central grooves, said grooves extending in depth less than the entire depth of the rails, thus providing shoulders at their bottoms,- and a replaceable tread-bridge rail-top insert accommodated in the said grooves resting on the bottom shoulders of said grooves and bridging the gap between the rail ends with the upper edge of the insert flush with rail heads, said insert being of a length shorter than the combined length of said grooves and the gap between the rail ends to provide gaps between the ends of said insert and the opposite end faces of the said grooves, a pair of bed plates extending laterally of said rails and spaced apart, longitudinally of said rails, a pair of bilateral chairs resting on said bed plates having wedge means for laterally bracing the said rai1 ends and for aligning the rails and the central grooves in the end portions of the rails, said insert having a downwardly projecting bottom lug adapted to be engaged in the space between the bed plates of the said chairs for the purpose of immovably anchoring the said insert irrespective of longitudinal movements of said rails.

2. A rail joint as defined in claim 1, and in which all of the upper edges of the rails where the grooves are formed and the upper edges of the insert are rounded off.

3. In a rail joint as defined in claim 1, and in which the upper parts of the recesses in the rails adjacent their ends are of the full width of the rail heads, the tread bridge insert having a central upper part of equal width to the rail head, said central part being disposed in the parts of the recesses of full rail head width, the parts of the recesses and the part of the insert which are of the full rail head width being symmetrical to the gap between the rails, and the part of the insert of full rail head width being of such length as to provide gaps between the ends thereof and the end faces of the parts of the recesses of full rail head width, the sum of widths of the latter gaps being equal to that of the gaps between the ends of said insert and the end faces of said recesses and also equal to the width of the gap between the rail ends.

HANS OTTO HOFFMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 526,954 Wells Oct. 2, 1894 641,101 Hachmann Jan. 9, 1900 730,556 McCully June 9, 1903 1,089,861 Osborn Mar. 10, 1914 1,118,620 Baling Nov. 24, 1914 1,960,331 Colbie May 29, 1934 FOREIGN PATENTS Number Country Date 565,805 Germany Dec. 8, 1932 

